[FFmpeg-devel] JPEG2000 decoder

[Rukhsana Ruby]

Hi Michael,

On Wed, Jul 27, 2011 at 4:45 PM, Rukhsana Ruby <rukhsana.afroz at gmail.com>wrote:

> Hi Michael,
>
> Will you be able to be online again on IRC? I truly appreciate your help.
>
> Thanks
>
>
> On Wed, Jul 20, 2011 at 5:54 PM, Rukhsana Ruby <rukhsana.afroz at gmail.com>wrote:
>
>> Hi Michael,
>>
>> I do not ask you to come online for hours, just for a few minutes. I found
>> arithmetic encoding is working for the current decode, but after decoding
>> component data differs between ours and jasper's. Its may be for our data
>> representation. If you could come online, I could show you data very easily
>> and this way my time would be saved a way more. In fact, I am stuck in this
>> position. I truly appreciate your help.
>>
>> Thanks
>>
>>
>> On Tue, Jul 19, 2011 at 1:25 PM, Rukhsana Ruby <rukhsana.afroz at gmail.com>wrote:
>>
>>> Hi Michael,
>>>
>>> Could you please be online on IRC for a while?
>>>
>>> Thanks
>>>
>>> On Fri, Jul 15, 2011 at 6:14 PM, Michael Niedermayer <michaelni at gmx.at>wrote:
>>>
>>>> On Sun, Jul 10, 2011 at 08:46:04AM -0700, rukhsana afroz wrote:
>>>> > Hi Michael,
>>>> >
>>>> > On Fri, Jul 8, 2011 at 4:57 AM, rukhsana afroz <
>>>> rukhsana.afroz at gmail.com>wrote:
>>>> >
>>>> > > Hi Michael,
>>>> > >
>>>> > >
>>>> > > On Thu, Jul 7, 2011 at 8:09 AM, rukhsana afroz <
>>>> rukhsana.afroz at gmail.com>wrote:
>>>> > >
>>>> > >> Hi Michael,
>>>> > >>
>>>> > >> Please respond to me whenever you see this message. I truly
>>>> appreciate
>>>> > >> your help. I will not take much of your time.
>>>> > >>
>>>> > >> Thanks
>>>> > >>
>>>> > >>
>>>> > >> On Thu, Jul 7, 2011 at 7:19 AM, rukhsana afroz <
>>>> rukhsana.afroz at gmail.com>wrote:
>>>> > >>
>>>> > >>> Hi Michael,
>>>> > >>>
>>>> > >>>
>>>> > >>> On Thu, Jul 7, 2011 at 7:11 AM, rukhsana afroz <
>>>> rukhsana.afroz at gmail.com
>>>> > >>> > wrote:
>>>> > >>>
>>>> > >>>> Hi Michael,
>>>> > >>>>
>>>> > >>>> It would be great if you could manage 10/20 minutes for me. In
>>>> your
>>>> > >>>> convenient time, I will be on IRC.
>>>> > >>>>
>>>> > >>>> Thanks
>>>> > >>>>
>>>> > >>>>
>>>> > >>>>
>>>> > >>>> On Wed, Jul 6, 2011 at 6:43 PM, rukhsana afroz <
>>>> > >>>> rukhsana.afroz at gmail.com> wrote:
>>>> > >>>>
>>>> > >>>>> Hi Michael,
>>>> > >>>>>
>>>> > >>>>> Are you in vacation? I dont see you online.  I urgently need
>>>> your help
>>>> > >>>>> on one thing. If you could tell me your convenient time, I can
>>>> be online on
>>>> > >>>>> IRC during that time.
>>>> > >>>>>
>>>> > >>>>>
>>>> > >>>>> Thanks
>>>> > >>>>>
>>>> > >>>>> --
>>>> > >>>>> Rukhsana Ruby
>>>> > >>>>> Phd Student
>>>> > >>>>> Department of Electrical & Computer Engineering
>>>> > >>>>> The University of British Columbia
>>>> > >>>>> ============================
>>>> > >>>>>
>>>> > >>>>>
>>>> > >>>>>
>>>> > >>>>
>>>> > >>>>
>>>> > >>>> --
>>>> > >>>>
>>>> > >>>>
>>>> > >>> The current bug is due to the incorrect calculation of band
>>>> coordiantes.
>>>> > >>> This is due to the following variables in SIZ marker:
>>>> > >>>
>>>> > >>> XRsizi:Horizontal separation of a sample of ith component with
>>>> respect to
>>>> > >>> the reference grid. There is one
>>>> > >>>       occurrence of this parameter for each component.
>>>> > >>> YRsizi:Vertical separation of a sample of ith component with
>>>> respect to
>>>> > >>> the reference grid. There is one
>>>> > >>>       occurrence of this parameter for each component.
>>>> > >>>
>>>> > >>> XRsizi: 2, YRsizi: 1 for the file p1_01.j2k. I am not very sure
>>>> how to
>>>> > >>> use these variables correctly to calculate band coordinate. I
>>>> truly
>>>> > >>> appreciate your help.
>>>> > >>>
>>>> > >>>
>>>> > >>> Thanks
>>>> > >>>
>>>> > >>>
>>>> > >>>
>>>> > > I have fixed the bug in the calculation of band coordinates. Now, I
>>>> have
>>>> > > found new bug. I need your help on this. If you could reply, that
>>>> would be
>>>> > > very helpful for me.
>>>> >
>>>> >
>>>> > I have fixed the bug on calculating the band coordinates and now
>>>> arithmetic
>>>> > encoding is working. I have one question, after dequantization before
>>>> > inverse wavelet transform, should the component data of our decoder
>>>> match
>>>> > with jasper's decoder. I am finding mismatch between both data.
>>>>
>>>> yes they should match.
>>>> It may be that the way things are stored differs, like sign/abs vs
>>>> twos completent or things like that but the values should (ignoring
>>>> how they are represented) match
>>>>
>>>>
>>>> > Also, I am
>>>> > getting memory leak while printing component data. My code for
>>>> printing
>>>> > component data is below:
>>>> >
>>>> > static void printcomp(J2kDecoderContext *s, J2kComponent *comp) {
>>>> >     int i, j;
>>>> >
>>>> >     av_log(s->avctx, AV_LOG_INFO, "y: %d\n", comp->coord[1][1] -
>>>> > comp->coord[1][0]);
>>>> >     for( i = 0; i < comp->coord[1][1] - comp->coord[1][0]; i++){
>>>> >        for( j = 0; j < comp->coord[0][1] - comp->coord[0][0]; j++)
>>>> >      av_log(s->avctx, AV_LOG_INFO, "0x%x ", *(comp->data + j));
>>>> >
>>>>
>>>> >        if (i < comp->coord[1][1] - comp->coord[1][0] - 1)
>>>> >             comp->data = comp->data + comp->coord[0][1] -
>>>> comp->coord[0][0];
>>>>
>>>> that does more than just printing
>>>> and to debug memleaks try valgrind, its quite powerfull and will
>>>> pinpoint exactly where the leak is
>>>>
>>>> [...]
>>>> --
>>>>
>>>

I have put two pastebins (with partial data) which are the component data
before dequantization. These data is for the file which can be decoded
correctly. I think, data representation is way different between ours and
jaspers and therefore we see the difference in each and every byte of
component data. I want to modify ffmpeg's code so that data representation
looks similar to jasper. Could you please tell me how i can do it?
Otherwise, its impossible to debug for the file which cannot be decoded at
all.

ffmpeg:
http://pastebin.com/kAMmZh30

jasper:
http://pastebin.com/mya6RxNS

Please get back to me as early as possible. I want to finish this work as
soon as possible. And sorry, I was busy with my school work last few days
and didnt work on it. Also, I am on IRC.

Thanks


-- 
Rukhsana Ruby
Phd Student
Department of Electrical & Computer Engineering
The University of British Columbia
============================